I'm checking the AIR forums daily (over at Adobe and Github) but there's no new of a new Harman runtime yet.

Have you found and tried Adobe AIR v20.0 yet?
As I mentioned over in your other forum thread, another Big Sur user has had success with v20.0 so it's worth trying.
In case you're having trouble finding it, it looks like mac.filehorse.com still has it available on their website.
Here's their download page for v20.0.0.260: https://mac.filehorse.com/download-adobe-air/6443/
I cannot vouch for the integrity of the file from this source (I cannot file file hashes for old AIR files on Adobe's website) but I've run the file through VirusTotal and it seems to be 100% clean.
I realise that this seems to be the only source that I can find for the only suggestion that I can think of that might help at the moment but, as the AIR installer is not coming directly from Adobe's own web site, please download and install at your own risk.

Unfortunately, there is no automated migration path from Koken to Juicebox.
You would need to recreate your galleries from scratch using JuiceboxBuilder-Pro and then embed the galleries into your web pages (assuming you have FTP access to the web space that your host provides) following the embedding instructions here.

I really dont see any shortcuts that you could take unless you are able to write a script (perhaps using a server-side scripting language such as PHP) to fetch the current image data from your database and use this information to build a Juicebox gallery's 'config.xml' configuration file. This would be a lot of work (and is beyond the scope of support that I am able to provide) and might only be beneficial if you have hundreds of galleries to convert (due to the complex and time-consuming nature of such a project).

I realise that this may not be the answer that you are looking for but creating galleries in JuiceboxBuilder (once you've got it up and running) is a quick and easy process and if you have data embedded within your source images, then JuiceboxBuilder can extract the IPTC Document Title (as the image title) and the IPTC Description (as the image caption) which would avoid the need to manually enter image titles and captions.

Adobe have passed the development and support of AIR to Harman but AIR is still an active and valid platform.

Unfortunately, now that Adobe have passed AIR to Harman, they have removed their regular Adobe AIR download page (redirecting users to the Harman site) and, at the moment, Harman provide only an AIR SDK (a Software Development Kit for developers) but not an AIR runtime (for AIR application end users).
Installing an AIR SDK will not allow you to run the JuiceboxBuilder installer. An AIR runtime is required.
This makes life a little difficult during this transitional period.

However, it is still possible to download the most recent AIR v32.0.0.125 runtime directly from Adobe via the links below:
Mac: https://download.macromedia.com/air/mac … obeAIR.dmg
Windows: https://download.macromedia.com/air/win … taller.zip

Once you have downloaded and installed AIR from the links above, you should be able to pick up the Installing JuiceboxBuilder instructions at Step #2.

At the moment, although Harman provide only an AIR SDK, they hope to provide an AIR runtime very soon.
According to a comment (from five days ago) on this web page, Andrew Frost (Harman's Software Engineering Manager) says:

In the meantime, until the Harman AIR runtime is made available, the most recent Adobe AIR runtime can be downloaded from the links above (or from software download sites such as Softpedia). However, if you download Adobe AIR from any website other than Adobe's own, then please do so at your own risk.
Incidentally, the most recent Adobe AIR beta runtimes (v32.0.0.144) can still be downloaded from the Adobe Labs page here.

I have notified the Juicebox developers of Adobe's website change and our installation instructions should be updated in our next website refresh.

Yes, but you'll need to implement the fix (first required for MacOS Catalina) noted here.

I hope this helps.

It sounds like a caching problem: either client side (in your browser) or server side.
Caching can be very useful but it can also be a hindrance when developing a web site.

First of all, try completely clearing your browser's cache before reloading your gallery's web page to ensure that your browser is using the latest versions of all the files fresh from your web server (instead of older, cached versions).
Alternatively, try viewing your gallery's web page using a different browser (one that you have not used to view your gallery's web page before): Chrome, Edge, Firefox, Opera or Safari.

There is a chance that your web host uses server-side caching and even though you upload new files via FTP, older versions of those file could still be served to browsers for a certain amount of time.

I have an account with a web host that uses Varnish server caching. After I upload a new version of a file to my web server, the new version is not seen (and the old version is still served) for about 20 minutes afterwards. For this reason, I have Varnish disabled.

Ask your web host if they have server-side caching enabled on your hosting account and, if so, ask if they could disable it.

If neither of the suggestions above help, then please post the link to your gallery's web page and let me know what you see and what you expect to see.
I'll take a look myself, let you know what I see and hopefully figure out what the problem is.
Thank you.

You'll likely need to run whatever editing program you use as an administrator (as well as being logged  on as an administrator).
Rather than just double-clicking your editing program's shortcut, right-click it and select 'Run as administrator'.

Incidentally, after opening your editing program via 'Run as administrator' you may not be able to drag and drop the 'index.html' file into the program. You may need to use the program's 'File -> Open' functionality to open the 'index.html' file instead.

I hope this helps.

If you edit a gallery using JuiceboxBuilder-Pro, then the only thing you need to update on your web server is the gallery's 'config.xml' file (which holds the gallery's configuration options and image data). (You'll also need to update the 'images' and 'thumbs' folders if you add any new images, though.)
There is no need to update the gallery's embedding code (unless you change the gallery's background color or dimensions) so you can leave this in place on your web server with no need to overwrite it with a version that does not contain the themeUrl.

If you use the gallery's own 'index.html' page (generated by JuiceboxBuilder-Pro) to display the gallery on its own web page (rather than embedding the gallery in an existing web page alongside other content) and are in the habit of uploading the entire gallery folder to your web server after editing, then you can modify the template file that JuiceboxBuilder-Pro uses to generate the 'index.html' page so that the themeUrl is present in every gallery you create and edit.

Open the following file in a plain text editor and add the themeUrl to the embedding code:
Windows: C:\Program Files (x86)\JuiceboxBuilder-Pro\template\index.html
Mac: /Applications/JuiceboxBuilder-Pro.app/Contents/Resources/template/index.html

For example:

<!--START JUICEBOX EMBED-->
<script src="jbcore/juicebox.js"></script>
<script>
    new juicebox({
        containerId: 'juicebox-container',
        galleryWidth: '%%WIDTH%%',
        galleryHeight: '%%HEIGHT%%',
        backgroundColor: '%%COLOR%%',
        themeUrl: '/my_themes/custom_theme/theme.css'
    });
</script>
<div id="juicebox-container"></div>
<!--END JUICEBOX EMBED-->

The leading slash in the themeUrl above denotes your root directory (i.e. the themeUrl is a relative path always starting at your root directory) so such a themeUrl would work in any page throughout your website without modification.

First, create a Juicebox gallery with JuiceboxBuilder (the desktop application to create and edit galleries).
You'll find details in the links below.

JuiceboxBuilder Tour: https://www.juicebox.net/tour/juiceboxbuilder/
JuiceboxBuilder User Guide: https://www.juicebox.net/support/juiceboxbuilder/
Getting Started Guide (inc. 5 minute video): https://www.juicebox.net/support/#getting-started

Then, you can either:
(1) View the gallery on a web page of its own by opening the 'index.html' file (inside the gallery folder) in a browser.
... or:
(2) Embed the gallery into an existing web page (alongside other content) by following the instructions in the Embedding Guide: https://www.juicebox.net/support/embedding/

Take a look at the short Adding a Logo support section for ideas as to how you could incorporate a logo into your Juicebox gallery.

If you use Suggestion #3 from the link above, then you can also make the logo into a link by using a Gallery Title such as:

<a href="http://www.example.com/index.html"><img src="mylogo.png"/></a>

As an alternative to using the Gallery Title, you could use the Back Button.
Set and backButtonUseIcon="FALSE" and the backButtonText will be used. instead of the 'home' icon. You can then set the backButtonText to be something like the HTML code above. (Also, be sure to set backButtonPosition to something other than NONE so that the Back Button appears in the gallery.)

For reference, a list of all Back Button options can be found here.
More information on using HTML formatting within the Gallery Title and Back Button can be found in this FAQ:
How do I add HTML formatting to the Gallery Title or Back Button?

I hope this helps.

@mustard

Technically, there really is no limit to the number of galleries that you can have on a single web page. (There is no hard-coded limit built into Juicebox.)

This sounds like a coding problem (maybe a duplicated baseUrl or configUrl).
Please post back with the URL to your web page so that I can see the problem for myself and hopefully help further.

Incidentally, when embedding multiple galleries, the 'juicebox.js' file should be loaded just once (i.e. once per web page rather than once per gallery). If you currently load the 'juicebox.js' file once per gallery, then leave the first instance and remove al others.

Thank you for the update. I'm glad you've been able to resolve your Lite/Pro problem.

You have two opening <script> tags one after another: one on line 97 and the other (after a few blank lines) on line 103.
After the initial opening <script> tag, the browser is expecting some JavaScript code but, instead, it encounters the '<' character of the next opening script> tag which is where the error is coming from.
Just remove one of these opening <script> tags and all should be well.

If you'd like to check your web page for any other HTML errors, you can feed your web page's URL to the W3C Markup Validation Service (and then fix any errors reported).

That's a strange solution, for sure, but I'm glad that it worked for you. Thank you for letting me know.

Incidentally, I just reinstalled Windows 10 myself last week (a clean install) and did not have to adjust my system clock to install JuiceboxBuilder-Pro so I'm really not sure what the cause of the problem is.
In any case, I'm glad you've got it working.

You're welcome!
I hope you get on OK with your other galleries.
I'll mark this thread as [SOLVED] but if you run into any further problems, just create a new thread and I'll do my best to help you out.